<?php
 
if(!$maxlength) $maxlength = 255;
$maxlength = min($maxlength,255);
$fieldtype = $issystem ?'CHAR': 'VARCHAR';
$sql = "ALTER TABLE `$tablename` CHANGE `$field` `$field` $fieldtype( $maxlength ) NOT NULL DEFAULT '$defaultvalue'";
$db->query($sql
?>